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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

37529 results found.

  1. GRB 150423A: VLT detection
  2. GRB 150423A: Swift-XRT refined Analysis
  3. GRB 150423A: RATIR optical afterglow monitoring
  4. GRB 150423A: Enhanced Swift-XRT position
  5. GRB 150422A: Fermi GBM detection
  6. GRB 150423A: Keck optical afterglow confirmation
  7. GRB 150423A: GROND afterglow candidate
  8. GRB 150413A: Konus-Wind and Swift/BAT joint spectral analysis
  9. GRB 150423A: KAIT Optical Upper Limit
  10. GRB 150423A: GROND observation
  11. GRB 150423A: Swift detection of a short burst
  12. Konus-Wind observation of GRB 150418A
  13. GRB150418A: Swift/UVOT did not detect a new source
  14. Further Swift XRT observations of GRB 150418A
  15. GRB 150413A: Swift-XRT observations
  16. GRB 150418A: Swift-XRT observations
  17. GRB 150413A: RTT150 optical observations
  18. GRB 150418A: Tiled Swift observations
  19. GRB 150418A: MAXI/GSC detection
  20. GRB 150413A: ISON-Ussuriysk optical observations
  21. GRB 150416A: Fermi GBM detection
  22. Confirmation that Swift trigger 638217 is not an astrophysical source
  23. GRB 150413A: MITSuME Akeno Optical observation
  24. GRB 150413A: SAO RAS observations
  25. LOAO B, R Observations of GRB150413A
  26. GRB 150416A: Fermi-LAT detection
  27. GRB 150413A: Refined redshift
  28. GRB 150413A: GMG observation
  29. GRB 150413A: AMI 15 GHz detection of possible radio counterpart
  30. GRB 150413A: additional P60 observations
  31. GRB 150413A : Virtual Telescope optical observations
  32. GRB 150413A
  33. GRB 150413A: Bassano Bresciano Observatory optical observations
  34. Konus-Wind observation of a bright burst from SGR 1935+2154
  35. GRB 150413A: T7 and T18 optical observations
  36. GRB 150413A: Swift-BAT refined analysis
  37. GRB150413A, optical observations
  38. IPN Triangulation of a bright burst from SGR 1935+2154
  39. GRB 150413A: optical observations
  40. GRB 150413A: redshift determination with the 2.2m CAHA
  41. GRB 150413A: P60 photometry
  42. GRB 150413A: Khureltogot optical observations
  43. GRB 150413A: Tautenburg observations
  44. GRB 150413A: Nanshan optical and radio follow-ups
  45. GRB 150413A: Khureltogot optical observations
  46. GRB 150413A: MAXI/GSC detection
  47. GRB 150413A: MASTER very bright unusual OT observations
  48. GRB 150413A: MASTER bright OT detection
  49. GRB 150413A: Swift detection of a burst
  50. GRB 150407A: Swift-XRT observations
  51. GRB 150407A: optical observations
  52. GRB 150407A: Swift detection of a possible burst
  53. GRB 150407A: Swift ToO observations
  54. GRB 150403A: MASTER-net optical observation
  55. GRB 150404A: Fermi GBM detection
  56. Konus-Wind observation of GRB 150403A
  57. Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
  58. GRB 150403A: Swift-BAT refined analysis
  59. GRB 150403A: Fermi GBM Detection
  60. GRB 150403A: Swift/UVOT Detection
  61. GRB 150403A: VLT/X-shooter redshift
  62. GRB 150323C: CrAO optical observations
  63. GRB 150323C: additional optical observations in Mondy
  64. GRB 150323C: Khureltogot optical observations
  65. GRB 150403A: Swift-XRT refined Analysis
  66. GRB 150403A: Fermi-LAT detection
  67. GRB 150403A: Enhanced Swift-XRT position
  68. GRB 150403A: Swift detection of a burst with an optical counterpart
  69. GRB 150402A: results of Swift observations
  70. GRB 150402A: RATIR Optical Observations
  71. GRB 150402A: Swift ToO observations
  72. GRB 150402A detected in ground analysis of Swift-BAT data
  73. Konus-Wind observation of GRB 150330A
  74. IPN Triangulation of GRB 150330A (long/very intense)
  75. GRB 150330A: Fermi GBM detection
  76. GRB 150323B: Swift-XRT afterglow detection
  77. GRB 141121A: GMG observation
  78. GRB 150323C: possible host galaxy detection
  79. GRB 141212A: GMG observation limit
  80. GRB 141220A: GMG observation limit
  81. GRB 141225A: GMG observation limit
  82. GRB 150120B: GMG observation
  83. GRB 150317A: likely host galaxy detection
  84. GRB 150323B: Khureltogot optical observations
  85. GRB 150323C: Nishi-Harima NIR Observations
  86. GRB 150323A: AAO optical observations
  87. GRB 150323C: MITSuME Akeno Optical observation
  88. GRB 150220A: Optical observations at Kyiv comet station
  89. GRB 150323C; Konkoly optical observations
  90. GRB 150323B; Konkoly optical observations
  91. GRB 150323A; Konkoly optical observations
  92. Konus-Wind observation of GRB 150323B
  93. Konus-Wind observation of GRB 150323A
  94. GRB 150323C: Mondy optical observations
  95. GRB 150323B : Xinglong TNT upper limit
  96. GRB 150323C, Swift-BAT refined analysis
  97. GRB 150323C: RATIR Optical Afterglow Observations - Errata
  98. GRB 150323C: Swift/UVOT Upper Limits
  99. GRB 150323B: Swift-XRT observations
  100. GRB 150323C: Enhanced Swift-XRT position

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